Sonar (SOund Navigation And Ranging) has long been used to detect waterborne or underwater objects. For example, sonar devices may be used to determine depth and bottom topography, detect fish, locate wreckage, etc. In this regard, due to the extreme limits to visibility underwater, sonar is typically the most accurate way to locate objects underwater. Sonar transducer elements, or simply transducers, may convert electrical energy into sound or vibrations at a particular frequency. A sonar sound beam is transmitted into and through the water and is reflected from objects it encounters. The transducer may receive the reflected sound (the “sonar returns”) and convert the sound energy into electrical energy. Based on the known speed of sound, it is possible to determine the distance to and/or location of the waterborne or underwater objects. The sonar return signals can also be processed to be displayed in graphical form on a display device, giving the user a “picture” of the underwater environment. The signal processor and display may be part of a unit known as a “sonar head” that is connected by a wire to the transducer mounted remotely from the sonar head. Alternatively, the sonar transducer may be an accessory for an integrated marine electronics system offering other features such as GPS, radar, etc.
Since the development of sonar, display technology has also been improved in order to enable better interpretation of sonar data. Strip chart recorders and other mechanical output devices have been replaced by, for example, digital displays such as LCDs (liquid crystal displays). Current display technologies continue to be improved in order to provide, for example, high quality sonar data on multi-color, high resolution displays having a more intuitive output than early sonar systems were capable of producing. Accordingly, it is desirable to provide improved sonar systems for better image quality.